A lever is the simplest kind of mechanism. There are three different types of lever. Common examples of each type are the crowbar, the wheelbarrow and the pair of tweezers.
All levers are one of three types, usually called classes. The class of a lever depends on the relative position of the load, effort and fulcrum:
- The load is the object you are trying to move.
- The effort is the force applied to move the load.
- The fulcrum (or pivot) is the point where the load is pivoted.
A class one lever has the load and effort on opposite sides on the fulcrum. E.g. a crowbar or a seesaw.
Remember class one
Load - Fulcrum - Effort
A class two lever is were the load and effort are on the same side but the load is nearer the fulcrum. E.g. a wheel barrow or nutcrackers
Remember class two
Fulcrum - Load - Effort
This type of lever is less common because it has no mechanical advantage. It is were the load and effort are on the same side, however for this class the effort is closer to the fulcrum. E.g. tweezers or barbeque prongs.
Remember class three
Fulcrum - Effort - Load